Armchair



FIG. 1 is a perspective view of an armchair, showing my new design from the front, right side and above;

FIG. 2 is a perspective view thereof from the front, left side and above;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a front elevational view thereof; and,

FIG. 5 is a top plan view thereof. 

The ornamental design for an armchair, as shown and described. 